Incorporation of fillers in elastomeric composites: impact of the process on the thermomechanical properties

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Incorporation of fillers in elastomeric composites: impact of the process on the thermomechanical properties

Adrien Simon, Daphné Berthier, Marie-Pierre Deffarges, Mathieu Venin, Florian Lacroix, Yoann Tendron, Stéphane Méo

To cite this version:

Adrien Simon, Daphné Berthier, Marie-Pierre Deffarges, Mathieu Venin, Florian Lacroix, et al.. Incor- poration of fillers in elastomeric composites: impact of the process on the thermomechanical properties.

IRC 2019, Sep 2019, London, United Kingdom. �hal-02294357�

Dispersion in solvent

 Order of incorporation

 Solvent, temperature, stirring rate

Deposition rate

100 200 300 400 500 600 700 800

0 20 40 60 80

100 Sheets

Thin films

Temperature (in ° C)

Weight loss (in %)

Test parameters : - 20°C/min

- Under air (80ml/min)

X = 1

1

Laboratoire de Mécanique Gabriel Lamé, Université de Tours, Université d’Orléans, INSA Centre Val de Loire, Polytech Tours, 7 avenue Marcel Dassault BP40, 37004 Tours, France

2

SAFRAN AEROSYSTEMS, 20 Avenue Georges Pompidou, 37600 Loches, France

*

In partnership with the LRCCP (Laboratoire de Recherche et de Contrôle du Caoutchouc et des Plastiques)

Conclusions

Polyhedral Oligomeric SilSesquioxanes (POSS)

R : non reactive group with R ≥ 1

 Smallest silica particles (1 to 3nm)

 Hybrid chemical composition

 Role of functionnal groups (X) : chemical interaction with polymers

X : functionnal group with X ≥ 1

Length Si-Si 0.5nm Length R-R 1.5nm

Mechanical behaviour

 A fourth monomer is incorporated to enhance the crosslinking action, named « Cure Site Monomer » (CSM)

 FKM exhibits good mechanical, chemical and thermal properties

Previous works [1] led to the development of a new formula on the basis of FKM blend reinforced with Polyhedral Oligomeric Silesesquioxanes (POSS). The main objective consists in maintaining thermomechanical properties while changing the process scale. To this end, two new specimen geometries of vulcanized rubber are studied : thin films obtained by coating at laboratory scale through masterbatch and sheets obtained through rubber mill and thermocompression.

[1] D. Berthier, M-P. Deffarges, N. Berton, M. Venin, F. Lacroix, B. Schmaltz, Y. Tendron, E. Pestel, F. Tran-Van, S. Méo. “POSS Nanofiller-Induced Enhancement of the Thermomechanical Properties in a Fluoroelastomer Terpolymer”, Materials, 11(8): 1358, 2018.

[2]

K. Raftopoulos, K. Pielichowski, « Segmental dynamics in hybrid polymer/POSS nanomaterials », Prog. Polym. Sci. 52 136–187, 2016.

[3]

S.-R. Tseng, H.-F. Meng, K.-C. Lee, and S.-F. Horng, “Multilayer polymer light-emitting diodes by blade coating method,” Appl. Phys. Lett., vol. 93, no. 15, p. 153308, Oct.

2008.

Formula of the terpolymer FKM

Possible interactions with a POSS (X=1) [2]

Chemical structure of POSS

Processes and geometries

 Impact of a new manufacturing way (tube by extrusion)

 Comparison between the three final products (thin film-sheet-tube)

Upgrade of the formula

 Incorporation of POSS with new functionnal groups

 Characterisation of materials after chemical and/or thermal aging

 Impact of the process and of the specimen geometries on the macroscopic mechanical characterisation (by tensile test : underestimation of the materials properties on thin films), on the glass transition and on the cross linking reaction (on activation energy and activation temperature)

 Presence of volatile compounds in thin films but not in sheets (TGA results)

 No impact on degradation behaviour

 Thin films is a cost efficient way to provide thermal informations before sheet fabrication

Perspectives

Incorporation of fillers in elastomeric composites: impact of the process on the thermomechanical properties

Adrien Simon, Daphné Berthier ² , Marie-Pierre Deffarges ¹ , Mathieu Venin ¹ , Florian Lacroix ¹ , Yohan Tendron ² , Stéphane Méo ¹

Fluorinated rubber: FKM

Thermal behaviour

ThermoGravimetric Analysis (TGA)

Differential Scanning Calorimetry (DSC)

Tensile tests at 23°C Dynamic Mechanical Analysis (DMA)

Two studied processes

Coating Thermocompression

1. Mixing step

2. Vulcanising process

(Vulcanization + Post- vulcanization)

3. Specimen geometries

Rubber mill

 Order of incorporation

 Rotation speed

 Temperature

Modulus at 100%

(in MPa)

Tensile at failure (in MPa)

Elongation at failure

(in %) Thin films 0.6 ± 0.05 2.4 ± 0.7 278 ± 45 Sheets 1.24 ± 0.01 11.2 ± 1.5 425 ± 30

 Same degradation trends

 For thin films, a slightly weight loss, is supposed to be associated to evaporation of volatile compounds (around 130°C)

 The glass transition (for raw and vulcanized samples), the activation temperature and the reaction area of the crosslinking reaction are higher by thermocompression than by coating

 Curve trends and failure parameters are differents between thin films and sheets

Tα (in °C) at 1 Hz Thin films 1.4 ± 0.2

Sheets 2.7 ± 0.6

 Tα: temperature at the maximum of the tan δ in the glass transition zone

Tα _Sheet > Tα _{Thin film}

-50 -25 0 25 50 75 100 125 150 175 200 225

Test parameters : - 20°C/min

- Cooling with nitrogen

H = -38,4 ± 2,5 J/g

Tg = -13,8 ± 1,2 °C Tg = -12,1 ± 0,7 °C

Tg = -15,6 ± 0,4 °C

H = -30,8 ± 2,7 J/g

Raw sheets

Vulcanized sheets Raw films

Vulcanized films

Heat flow (in W/g)

Temperature (in ° C)

Endo 0,1 W/g

Tg = -18,8 ± 0,6 °C

-25 -20 -15 -10 -5 0 5 10 15 20 25 30 35 40 45 50 0,0

0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6 1,8

Test parameters :

- Heating rate : 3°C/min - Type of clamp : Tension - Frequency : 1Hz

- Amplitude : 10 µm Sheets

Thin films

Tan delta

Temperature (in °C)

[3]

T degradation at 50 % = 488 °C

 Cycles (Temperature, time)

 Specimen volume ≈ 0,4 cm ³

Thin films

 Dimension:

Thickness : around 400 µm

 Cycles (Temperature, time, pressure)

 Specimen volume ≈ 40 cm ³

Sheets

 Dimension:

Thickness : around 2 mm

0 50 100 150 200 250 300 350 400 450 500 0

2 4 6 8 10 12 14

Test parameters : - ISO 37

Sheets Thin films

Tensile stress (in MPa)

Engineer deformation (in %)